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1.
《Biochimica et Biophysica Acta - Proteins and Proteomics》2023,1871(4):140914
Magic mushrooms, and their extract psilocybin, are well-known for their psychedelic properties and recreational use. Psilocin, the bio-active form of psilocybin, can potentially treat various psychiatric diseases. Psilocin putatively exerts its psychedelic effect as an agonist to the serotonin 2A receptor (5-HT2AR), which is also the receptor for the neurological hormone serotonin. The two key chemical differences between the two molecules are first, that the primary amine in serotonin is replaced with a tertiary amine in psilocin, and second, the hydroxyl group is substituted differently on the aromatic ring. Here, we find that psilocin can bind to 5-HT2AR with an affinity higher than serotonin, and provide the molecular logic behind the higher binding affinity of psilocin using extensive molecular dynamics simulations and free energy calculations. The binding free energy of psilocin is dependent upon the protonation states of the ligands, as well as that of the key residue in the binding site: Aspartate 155. We find that the tertiary amine of psilocin, and not the altered substitution of the hydroxyl group in the ring is responsible for the increased affinity of psilocin. We propose design rules for effective antidepressants based on molecular insights from our simulations. 相似文献
2.
(1) The serotonin1A receptor is a G-protein coupled receptor involved in several cognitive, behavioral, and developmental functions. It binds
the neurotransmitter serotonin and signals across the membrane through its interactions with heterotrimeric G-proteins. (2)
Lipid–protein interactions in membranes play an important role in the assembly, stability, and function of membrane proteins.
The role of membrane environment in serotonin1A receptor function is beginning to be addressed by exploring the consequences of lipid manipulations on the ligand binding
and G-protein coupling of serotonin1A receptors, the ability to functionally solubilize the serotonin1A receptor, and the factors influencing the membrane organization of the serotonin1A receptor. (3) Recent developments involving the application of detergent-based and detergent-free approaches to understand
the membrane organization of the serotonin1A receptor under conditions of ligand activation and modulation of membrane lipid content, with an emphasis on membrane cholesterol,
are described. 相似文献
3.
Andr��s Norambuena Francisco Palma M. In��s Poblete M. Ver��nica Donoso Evelyn Pardo Alfonso Gonz��lez J. Pablo Huidobro-Toro 《The Journal of biological chemistry》2010,285(5):2940-2950
Extracellular nucleotides transmit signals into the cells through the P2 family of cell surface receptors. These receptors are amply expressed in human blood vessels and participate in vascular tone control; however, their signaling mechanisms remain unknown. Here we show that in smooth muscle cells of isolated human chorionic arteries, the activation of the P2Y2 receptor (P2Y2R) induces not only its partition into membrane rafts but also its rapid internalization. Cholesterol depletion with methyl-β-cyclodextrin reduced the association of the agonist-activated receptor into membrane rafts but did not affect either the UTP-mediated vasoconstrictions or the vasomotor responses elicited by both serotonin and KCl. Ex vivo perfusion of human chorionic artery segments with 1–10 μm UTP, a selective P2Y2R agonist, displaced the P2Y2R localization into membrane rafts within 1 min, a process preceded by the activation of both RhoA and Rac1 GTPases. AG1478, a selective and potent inhibitor of the epidermal growth factor receptor tyrosine kinase activity, not only blocked the UTP-induced vasomotor activity but also abrogated both RhoA and Rac1 activation, the P2Y2R association with membrane rafts, and its internalization. Altogether, these results show for the first time that the plasma membrane distribution of the P2Y2R is transregulated by the epidermal growth factor receptor, revealing an unsuspected functional interplay that controls both the membrane distribution and the vasomotor activity of the P2Y2R in intact human blood vessels. 相似文献
4.
The interpretation of experimental observations of the dependence of membrane protein function on the properties of the lipid membrane environment calls for a consideration of the energy cost of protein-bilayer interactions, including the protein-bilayer hydrophobic mismatch. We present a novel (to our knowledge) multiscale computational approach for quantifying the hydrophobic mismatch-driven remodeling of membrane bilayers by multihelical membrane proteins. The method accounts for both the membrane remodeling energy and the energy contribution from any partial (incomplete) alleviation of the hydrophobic mismatch by membrane remodeling. Overcoming previous limitations, it allows for radially asymmetric bilayer deformations produced by multihelical proteins, and takes into account the irregular membrane-protein boundaries. The approach is illustrated by application to two G-protein coupled receptors: rhodopsin in bilayers of different thickness, and the serotonin 5-HT2A receptor bound to pharmacologically different ligands. Analysis of the results identifies the residual exposure that is not alleviated by bilayer adaptation, and its quantification at specific transmembrane segments is shown to predict favorable contact interfaces in oligomeric arrays. In addition, our results suggest how distinct ligand-induced conformations of G-protein coupled receptors may elicit different functional responses through differential effects on the membrane environment. 相似文献
5.
Lipid Segregation and Membrane Budding Induced by the Peripheral Membrane Binding Protein Annexin A2
Patrick Drücker Milena Pejic Hans-Joachim Galla Volker Gerke 《The Journal of biological chemistry》2013,288(34):24764-24776
The formation of dynamic membrane microdomains is an important phenomenon in many signal transduction and membrane trafficking events. It is driven by intrinsic properties of membrane lipids and integral as well as membrane-associated proteins. Here we analyzed the ability of one peripherally associated membrane protein, annexin A2 (AnxA2), to induce the formation of phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2)-rich domains in giant unilamellar vesicles (GUVs) of complex lipid composition. AnxA2 is a cytosolic protein that can bind PI(4,5)P2 and other acidic phospholipids in a Ca2+-dependent manner and that has been implicated in cellular membrane dynamics in endocytosis and exocytosis. We show that AnxA2 binding to GUVs induces lipid phase separation and the recruitment of PI(4,5)P2, cholesterol and glycosphingolipids into larger clusters. This property is observed for the full-length monomeric protein, a mutant derivative comprising the C-terminal protein core domain and for AnxA2 residing in a heterotetrameric complex with its intracellular binding partner S100A10. All AnxA2 derivatives inducing PI(4,5)P2 clustering are also capable of forming interconnections between PI(4,5)P2-rich microdomains of adjacent GUVs. Furthermore, they can induce membrane indentations rich in PI(4,5)P2 and inward budding of these membrane domains into the lumen of GUVs. This inward vesiculation is specific for AnxA2 and not shared with other PI(4,5)P2-binding proteins such as the pleckstrin homology (PH) domain of phospholipase Cδ1. Together our results indicate that annexins such as AnxA2 can efficiently induce membrane deformations after lipid segregation, a mechanism possibly underlying annexin functions in membrane trafficking. 相似文献
6.
Single-Molecule Fluorescence Studies of a PH Domain: New Insights into the Membrane Docking Reaction
Jefferson D. Knight 《Biophysical journal》2009,96(2):566-582
Proteins containing membrane targeting domains play essential roles in many cellular signaling pathways. However, important features of the membrane-bound state are invisible to bulk methods, thereby hindering mechanistic analysis of membrane targeting reactions. Here we use total internal reflection fluorescence microscopy (TIRFM), combined with single particle tracking, to probe the membrane docking mechanism of a representative pleckstrin homology (PH) domain isolated from the general receptor for phosphoinositides, isoform 1 (GRP1). The findings show three previously undescribed features of GRP1 PH domain docking to membranes containing its rare target lipid, phosphatidylinositol (3,4,5)-trisphosphate [PI(3,4,5)P3]. First, analysis of surface diffusion kinetics on supported lipid bilayers shows that in the absence of other anionic lipids, the PI(3,4,5)P3-bound protein exhibits the same diffusion constant as a single lipid molecule. Second, the binding of the anionic lipid phosphatidylserine to a previously unidentified secondary binding site slows both diffusion and dissociation kinetics. Third, TIRFM enables direct observation of rare events in which dissociation from the membrane surface is followed by transient diffusion through solution and rapid rebinding to a nearby, membrane-associated target lipid. Overall, this study shows that in vitro single-molecule TIRFM provides a new window into the molecular mechanisms of membrane docking reactions. 相似文献
7.
Magnani F Tate CG Wynne S Williams C Haase J 《The Journal of biological chemistry》2004,279(37):38770-38778
The serotonin transporter (SERT) is an integral membrane protein responsible for the clearance of serotonin from the synaptic cleft following the release of the neurotransmitter. SERT plays a prominent role in the regulation of serotoninergic neurotransmission and is a molecular target for multiple antidepressants as well as substances of abuse. Here we show that SERT associates with lipid rafts in both heterologous expression systems and rat brain and that the inclusion of the transporter into lipid microdomains is critical for serotonin uptake activity. SERT is present in a subpopulation of lipid rafts, which is soluble in Triton X-100 but insoluble in other non-ionic detergents such as Brij 58. Disaggregation of lipid rafts upon depletion of cellular cholesterol results in a decrease of serotonin transport capacity (V(max)), due to the reduction of turnover number of serotonin transport. Our data suggest that the association of SERT with lipid rafts may represent a mechanism for regulating the transporter activity and, consequently, serotoninergic signaling in the central nervous system, through the modulation of the cholesterol content in the cell membrane. Furthermore, SERT-containing rafts are detected in both intracellular and cell surface fractions, suggesting that raft association may be important for trafficking and targeting of SERT. 相似文献
8.
Thomas J. Pucadyil 《生物化学与生物物理学报:生物膜》2005,1714(1):35-42
The serotonin1A receptor is the most extensively studied member of the family of seven transmembrane domain G-protein coupled serotonin receptors. Serotonergic signaling appears to play a key role in the generation and modulation of various cognitive and behavioral functions such as sleep, mood, pain, addiction, locomotion, sexual activity, depression, anxiety, alcohol abuse, aggression and learning. Since a significant portion of the protein lies embedded in the membrane and the ligand-binding pocket is defined by the transmembrane stretches in such receptors, membrane composition and organization represent a crucial parameter in the structure-function analysis of G-protein coupled receptors. In this paper, we have monitored the role of membrane cholesterol in the ligand-binding function of the hippocampal serotonin1A receptor. Our results demonstrate that the reduction of membrane cholesterol significantly attenuates the antagonist-binding function of the serotonin1A receptor. Based on prior pharmacological knowledge regarding the requirements for the antagonist to bind the receptor, our results indicate that membrane cholesterol modulates receptor function independently of its ability to interact with G-proteins. These effects on ligand-binding function of the receptor are predominantly reversed upon cholesterol-replenishment of cholesterol-depleted membranes. When viewed in the light of our earlier results on the effect of cholesterol depletion on the serotonin1A receptor/G-protein interaction, these results comprehensively demonstrate the importance of cholesterol in the serotonin1A receptor function and form the basis for understanding lipid-protein interactions involving this important neuronal receptor. 相似文献
9.
Depression is one of the most common psychiatric diseases in the population. Agomelatine is a novel antidepressant drug with melatonin receptor agonistic and serotonin 5-HT2C antagonistic properties. Furthermore, being a melatonergic drug, agomelatine has the potential of being used in therapeutic applications like melatonin as an antioxidant, anti-inflammatory and antiapoptotic drug. The action mechanism of agomelatine on the membrane structure has not been clarified yet. In the present study, we aimed to investigate the interaction of agomelatine with model membranes of dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylgylcerol (DPPG) by Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). We found that agomelatine interacts with the head group in such a manner that it destabilizes the membrane architecture to a large extent. Thus, agomelatine causes alterations in the order, packing and dynamics of the DPPC and DPPG model membranes. Our results suggest that agomelatine strongly interacts with zwitterionic and charged membrane phospholipids. Because lipid structure and dynamics may have influence on the structure of membrane bound proteins and affect the signal transduction systems of membranes, these effects of agomelatine may be important in its action mechanism. 相似文献
11.
《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2016,1861(11):1775-1786
G proteins are peripheral membrane proteins which interact with the inner side of the plasma membrane and form part of the signalling cascade activated by G protein-coupled receptors (GPCRs). Since many signalling proteins do not appear to be homogeneously distributed on the cell surface, they associate in particular membrane regions containing specific lipids. Therefore, protein–lipid interactions play a pivotal role in cell signalling. Our previous results showed that although Gαs and Gαi3 prefer different types of membrane domains they are both co-localized with the D1 receptor. In the present report we characterize the role of cholesterol and sphingolipids in the membrane localization of Gαs, Gαi3 and their heterotrimers, as well as the D1 receptor. We measured the lateral diffusion and membrane localization of investigated proteins using fluorescence recovery after photobleaching (FRAP) microscopy and fluorescence resonance energy transfer (FRET) detected by lifetime imaging microscopy (FLIM). The treatment with either methyl-β-cyclodextrin or Fumonisin B1 led to the disruption of cholesterol–sphingolipids containing domains and changed the diffusion of Gαi3 and the D1 receptor but not of Gαs. Our results imply a sequestration of Gαs into cholesterol-independent solid-like membrane domains. Gαi3 prefers cholesterol-dependent lipid rafts so it does not bind to those domains and its diffusion is reduced. In turn, the D1 receptor exists in several different membrane localizations, depending on the receptor's conformation. We conclude that the inactive G protein heterotrimers are localized in the low-density membrane phase, from where they displace upon dissociation into the membrane-anchor- and subclass-specific lipid domain. 相似文献
12.
Antonin Lamazière Ofelia Maniti Claude Wolf Olivier Lambert Gérard Chassaing Germain Trugnan Jesus Ayala-Sanmartin 《生物化学与生物物理学报:生物膜》2010,1798(12):2223-2230
Protein membrane transduction domains are able to translocate through cell membranes. This capacity resulted in new concepts on cell communication and in the design of vectors for internalization of active molecules into cells. Penetratin crosses the plasma membrane by a receptor and metabolic energy-independent mechanism which is at present unknown. A better knowledge of its interaction with phospholipids will help to understand the molecular mechanisms of cell penetration. Here, we investigated the role of lipid composition on penetratin induced membrane perturbations by X-ray diffraction, microscopy and 31P-NMR. Penetratin showed the ability to induce phospholipid domain separation, membrane bilayer thickening, formation of vesicles, membrane undulations and tubular pearling. These data demonstrate its capacity to increase membrane curvature and suggest that dynamic phospholipid–penetratin complexes can be organized in different structural arrangements. These properties and their implications in peptide membrane translocation capacity are discussed. 相似文献
13.
《生物化学与生物物理学报:生物膜》2021,1863(12):183761
Dendrimers are individual macromolecular compounds having a great potential for biomedical application. The key step of the cell penetration by dendrimers is the interaction with lipid bilayer. Here, the interaction between cationic pyridylphenylene dendrimer of third generation (D350+) and multicomponent liquid (CL/POPC), solid (CL/DPPC) and cholesterol-containing (CL/POPC/30% Chol) anionic liposomes was investigated by dynamic light scattering, fluorescence spectroscopy, conductometry, calorimetric studies and molecular dynamic (MD) simulations. Microelectrophoresis and MD simulations revealed the interaction is electrostatic and reversible with only part of pyridinium groups of dendrimers involved in binding with liposomes. The ability of dendrimer molecules to migrate between liposomes was discovered by the labeling liposomes with Rhodamine B. The phase state of the lipid membrane and the incorporation of cholesterol into the lipid bilayer were found to not affect the mechanism of the dendrimer - liposome complex formation. Rigid dendrimer adsorption on liposomal surface does not induce the formation of significant defects in the lipid membrane pave the way for possible biological application of pyridylphenylene dendrimers. 相似文献
14.
David L. Gray Wenjian Xu Brian M. Campbell Amy B. Dounay Nancy Barta Susan Boroski Lynne Denny Lori Evans Nancy Stratman Al Probert 《Bioorganic & medicinal chemistry letters》2009,19(23):6604-6607
Compounds that are both norepinephrine reuptake inhibitors (NRI) and 5-HT1A partial agonists may have the potential to treat neuropsychiatric disorders including attention deficit hyperactivity disorder (ADHD) and depression. Targeted screening of NRI-active compounds for binding to the 5-HT1A receptor provided a series of thiomorpholinone hits with this dual activity profile. Several iterations of design, synthesis, and testing led to substituted piperidine diphenyl ethers which are potent NRIs with 5-HT1A partial agonist properties. In addition, optimization of these molecules provided compounds which exhibit selectivity for NRI over the dopamine (DAT) and serotonin (SERT) reuptake transporters. Monoamine and 5-HT1A in vitro functional activities for select compounds from the developed piperidine diphenyl ether series are also presented. 相似文献
15.
G. N. Reiner L. Delgado-Marín N. Olguín S. Sánchez-Redondo M. Sánchez-Borzone E. Rodríguez-Farré C. Suñol D. A. García 《Cell biochemistry and biophysics》2013,67(2):515-525
Phenol compounds, such as propofol and thymol, have been shown to act on the GABAA receptor through interaction with specific sites of this receptor. In addition, considering the high lipophilicity of phenols, it is possible that their pharmacological activity may also be the result of the interaction of phenol molecules with the surrounding lipid molecules, modulating the supramolecular organization of the receptor environment. Thus, in the present study, we study the pharmacological activity of some propofol- and thymol-related phenols on the native GABAA receptor using primary cultures of cortical neurons and investigate the effects of these compounds on the micro viscosity of artificial membranes by means of fluorescence anisotropy. The phenol compounds analyzed in this article are carvacrol, chlorothymol, and eugenol. All compounds were able to enhance the binding of [3H]flunitrazepam with EC50 values in the micromolar range and to increase the GABA-evoked Cl? influx in a concentration-dependent manner, both effects being inhibited by the competitive GABAA antagonist bicuculline. These results strongly suggest that the phenols studied are positive allosteric modulators of this receptor. Chlorothymol showed a bell-type effect, reducing its positive effect at concentrations >100 μM. The concentrations necessary to induce positive allosteric modulation of GABAA receptor were not cytotoxic. Although all compounds were able to decrease the micro viscosity of artificial membranes, chlorothymol displayed a larger effect which could explain its effects on [3H]flunitrazepam binding and on cell viability at high concentrations. Finally, it is suggested that these compounds may exert depressant activity on the central nervous system and potentiate the effects of general anesthetics. 相似文献
16.
The G-protein coupled receptor (GPCR) superfamily is one of the largest classes of molecules involved in signal transduction across the plasma membrane. The serotonin(1A) receptor is a representative member of the GPCR superfamily and serves as an important target in the development of therapeutic agents for neuropsychiatric disorders such as anxiety and depression. In the context of the pharmacological relevance of the serotonin(1A) receptor, the membrane organization and dynamics of this receptor in the cellular environment assume relevance. We have highlighted results, obtained from fluorescence microscopy-based approaches, related to domain organization and dynamics of the serotonin(1A) receptor. A fraction of serotonin(1A) receptors displays detergent insolubility, monitored using green fluorescent protein, that increases upon depletion of membrane cholesterol. Fluorescence recovery after photobleaching measurements with varying bleach spot sizes show that lateral diffusion parameters of serotonin(1A) receptors in normal cells are consistent with models describing diffusion of molecules in a homogenous membrane. Interestingly, these characteristics are altered in cholesterol-depleted cells. Taken together, we conclude that the serotonin(1A) receptor exhibits dynamic confinement in the cellular plasma membranes. Progress in understanding GPCR organization and dynamics would result in better insight into our overall understanding of GPCR function in health and disease. 相似文献
17.
《Journal of molecular biology》2019,431(8):1633-1649
Despite the ubiquity of cholesterol within the cell membrane, the mechanism by which it influences embedded proteins remains elusive. Numerous G-protein coupled receptors exhibit dramatic responses to membrane cholesterol with regard to the ligand-binding affinity and functional properties, including the 5-HT receptor family. Here, we use over 25 μs of unbiased atomistic molecular dynamics simulations to identify cholesterol interaction sites in the 5-HT1B and 5-HT2B receptors and evaluate their impact on receptor structure. Susceptibility to membrane cholesterol is shown to be subtype dependent and determined by the quality of interactions between the extracellular loops. Charged residues are essential for maintaining the arrangement of the extracellular surface in 5-HT2B; in the absence of such interactions, the extracellular surface of the 5-HT1B is malleable, populating a number of distinct conformations. Elevated cholesterol density near transmembrane helix 4 is considered to be conducive to the conformation of extracellular loop 2. Occupation of this site is also shown to be stereospecific, illustrated by differential behavior of nat-cholesterol isomers, ent- and epi-cholesterol. In simulations containing the endogenous agonist, serotonin, cholesterol binding at transmembrane helix 4 biases bound serotonin molecules toward an unexpected binding mode in the extended binding pocket. The results highlight the capability of membrane cholesterol to influence the mobility of the extracellular surface in the 5-HT1 receptor family and manipulate the architecture of the extracellular ligand-binding pocket. 相似文献
18.
The present investigation was designed to determine the effect of hallucinogens on the facilitating action of serotonin (5-HT) and norepinephrine (NE) in the facial nucleus. Intravenous administration of d-lysergic acid diethylamide (LSD, 5–10 μg/kg), mescaline (0.5–1.0 mg/kg), or psilocin (0.5–1.0 mg/kg) had no effect by themselves on the glutamate-induced excitation of facial motoneurons. In contrast, the facilitation of facial neuron excitation by iontophoretically applied 5-HT and NE was enhanced 6–10 fold by these hallucinogens. The LSD-enhanced responses to 5-HT and NE continued for at least 4 hours after administration of the hallucinogen. Iontophoretic application of LSD or mescaline (low currents) also markedly potentiated the facilitating effect of 5-HT and NE. Higher currents of LSD (15–40 nA) temporarily antagonized the response to 5-HT. The nonhallucinogen ergot derivatives lisuride and methysergide failed to potentiate the facilitating effects of 5-HT or NE. These observations suggest that hallucinogens potentiate the effect of monoamines on facial motoneurons by increasing the sensitivity of 5-HT and NE receptors. A novel mechanism regarding the psychedelic effects of hallucinogens is discussed. 相似文献
19.
Magic angle spinning (MAS) NMR has been used to investigate the location and orientation of five serotonin receptor 1a agonists (serotonin, buspirone, quipazine, 8-OH-DPAT, and LY-163,165) in single component model lipid and brain lipid membranes. The agonist locations are probed by monitoring changes in the lipid proton chemical shifts and by MAS-assisted nuclear Overhauser enhancement spectroscopy, which indicates the orientation of the agonists with respect to the 1,2-dioleoyl-sn-glycero-3-phosphocholine lipids. In the single component bilayer, the membrane agonists are found predominantly in the top of the hydrophobic chain or in the glycerol region of the membrane. Most of the agonists orient approximately parallel to the membrane plane, with the exception of quipazine, whose piperazine ring is found in the glycerol region, whereas its benzene ring is located within the lipid hydrophobic chain. The location of the agonist in brain lipid membranes is similar to the 1,2-dioleoyl-sn-glycero-3-phosphocholine lipid bilayers; however, many of the agonists appear to locate close to the cholesterol in the membrane in preference to the phospholipids. 相似文献
20.
Shanti Kalipatnapu 《Molecular membrane biology》2013,30(6):539-547
Insolubility in non-ionic detergents such as Triton X-100 at low temperature is a widely used biochemical criterion for characterization of membrane domains. In view of the emerging role of membrane organization in the function of G-protein coupled receptors, we have examined detergent insolubility of the 5-HT1A receptor in CHO cells using a novel GFP fluorescence approach developed by us. Using this approach, we have explored the membrane organization of the serotonin1A receptor tagged to enhanced yellow fluorescent protein (5-HT1AR-EYFP) stably expressed in CHO-K1 cells under conditions of varying detergent concentration, reduced membrane cholesterol and agonist stimulation. Our results show that a small yet significant fraction of the 5-HT1A receptor exhibits detergent insolubility, which increases upon depletion of membrane cholesterol. Stimulation of 5-HT1AR-EYFP by its endogenous ligand, serotonin, did not cause a significant change in the detergent insolubility of the receptor. Taken together, our results on detergent insolubility of 5-HT1AR-EYFP provide new insights into the membrane organization of the 5-HT1A receptor and could be relevant in the analysis of membrane organization of other G-protein coupled receptors. 相似文献